Search for dissertations about: "Usnea"

Found 4 swedish dissertations containing the word Usnea.

  2. 1. Lichens in Mountain Rainforests of Tanzania : Studies of Usnea and Calicioids

    Author : Stella Gilbert Temu; Sanja Tibell Savić; Leif Tibell; Philippe Clerc; Göran Thor; Donatha Tibuhwa; Einar Timdal; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Lichens; Usnea; calicioids; molecular phylogeny; secondary chemistry; morphotypes; Biology with specialization in Systematics; Biologi med inriktning mot systematik;

    Abstract : Lichens occur in various habitats. They often have narrow niches and are sensitive to environmental changes leading to their use as bioindicators of environmental disturbances and conditions; air and heavy metal pollution, agricultural toxins, assessing forest continuity and drought tolerance. READ MORE

  4. 2. Phylogenetic Studies in Usnea (Parmeliaceae) and Allied Genera

    Author : Kristina Articus; Leif Tibell; Mats Wedin; Jan-Eric Mattsson; Philippe Clerc; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Biology; Usnea; Neuropogon; Dolichousnea; Eumitria; Protousnea; Parmeliaceae; phylogeny; taxonomy; species pairs; morphology; ITS-LSU; β-tubulin; mtSSU; Biologi; Biology; Biologi;

    Abstract : This thesis deals with the phylogeny of the lichen genus Usnea (Parmeliaceae, Ascomycetes). The relationships and the morphological variation among Usnea species has been studied, as well as the relationship of Usnea to allied genera. Two species, U. florida and U. READ MORE

  5. 3. Ecology of lichens in boreal coniferous forests with reference to spatial and temporal patterns

    Author : Per-Anders Esseen; Lars Ericson; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Lichens; epiphytes; Alectoria; Bryoria; Cladonia; Usnea; Picea abies; Pinus sylvestris; dispersal; litterfall; succession; diversity; spatial patterns;

    Abstract : The thesis deals with the ecology of lichens in two contrasting types of forest, epiphytic lichens in old Picea abies forest of the fi re-refugia type and epigeic as well as epixylic lichens in a successional sequence of fire- susceptible Pinus sylvestris forests. Results in five separate papers form the basis for a discussion of general patterns of dispersal, succession and life strategies in lichens. READ MORE

  6. 4. Forest edges in boreal landscapes - factors affecting edge influence

    Author : Ulrika Jansson; Per-Anders Esseen; Mats Nilsson; Timo Kuuluvainen; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; aerial photographs; edge contrast; edge density; edge length; fetch size; forest fragmentation; lichen growth; line intersect sampling; pendulous lichen; photo interpretation; skogskant; flygbild; kantlängd; lav; Terrestrial ecology; Terrestisk ekologi; ekologisk botanik; Ecological Botany;

    Abstract : The boreal forest in Fennoscandia has been subjected to major loss and fragmentation of natural forests due to intensive forestry. This has resulted in that forest edges are now abundant and important landscape features. Edges have documented effects on the structure, function and biodiversity in forests. READ MORE